Radio head

It's one of the most difficult questions in all radio: "Curses, this character is a child. What shall we do to make someone sound like a child?" Last Saturday's The Wire (Radio 3's new writing showcase, since you ask, and very good, despite what I'm about to say) answered it in a totally novel way. In I Can See You, they found a different actor to play the lead as an eight-year-old, but nothing so conven- tional as an actual eight-year-old: no, another adult, talking Kid with a Kapital K. What on earth is the point of that? If you're not going to get a proper kid to do it, isn't there a cast member who can multi-task? We all know the person pretending to be eight isn't eight, why not just get a machine to do it?

· The Archers (Radio 4), meanwhile, is getting a machine to do it - specifically, Jamie Perks, whose rare flashes of 12-year-old opinion are related to the rest of the dialogue but sound as if they were dropped in afterwards. The overall effect is as if you had texted a question to your own landline, put it on speakerphone, answered it, and were sitting in, pretending to have a conversation with Tom Baker. It works, but it also profoundly doesn't work.

You have to wonder, why is it so hard? Surely child actors are just like adult ones. You ring their agent, ask them to do stuff, pay them . . . Yes, they have school. But if they have time for extramural activities like drinking in bus shelters, how can they not have time for a modest amount of radio acting? I can only conclude that it's because they just don't do it right. They find it hard to keep the scepticism out of their little voices. Especially the ones on Go for It, sorry, Go 4 It (Sundays, Radio 4). You can hear what's going on inside the blighters' heads, and it's this: "We'll do this to keep you happy, you funny olds, but haven't you ever heard of telly?"

· I am going to look right stupid, now, if it turns out there are two up-and-coming radio actors called Anna Bengo, one in her 20s, and the other one, like, nine. But it's a risk I'm prepared to take, reader.